Pervasive Dolomitization and its Effects on Reservoir Quality of the Jahrum Formation in the North and Northwestern Bandar-Abbas

In this paper, we aim to recognize the different types of Jahrum dolomite and also to discuss the effects of dolomitization on the reservoir quality of the Jahrum formation in Bandar-Abbas region. For these purposes, we used a combination of two subsurface well sections at the Sarkhun-14 and West-Namak-01 gas-fields along with two outcrops (Finu and Khush anticlines). The lower stratigraphic intervals of the Jahrum formation were strongly altered by dolomitizing fluids. Based on petrographic observation by using polarized light, cathodoluminescence, and scanning electron microscopes, four different types of dolomite were distinguished. These data indicated that, when pervasive dolomitization occurred at the lower stratigraphic interval of Jahrum formation, this could be considered as suitable reservoir rocks and the effects of Mg-fluids on previous carbonate rocks formed abundant biomouldic porosity as a result of the dissolution of large benthic foraminifera.